| Atmospheric aerosols directly affect climate by scattering and absorbing incident solar radiation. The magnitude of the impact is dependent upon the wavelength of incoming light, but is typically approximated near 550 nm. As a result, climate models can have large uncertainties for aerosol contributions when considering the solar spectrum. An aerosol differential optical absorption spectrometer (A-DOAS) has been developed to address to measure aerosol extinction from mid-ultraviolet to near infrared. The instrument consists of a closed UV-Vis spectrometer coupled to a White-type multi-pass gas cell with an adjustable path length of up to 20 meters. Laboratory extinction measurements of polystyrene latex spheres, nigrosin dye, and carbon black are compared with theory to validate the new instrument. Further, the lower limit of detection for the A-DOAS is shown to be less than 1x10-7 cm-1 . Finally, ambient aerosols under a variety of conditions were monitored and future work suggestions are made. |
